This invention relates to photonic switch systems.
The demand for high-speed communication networks has increased dramatically over the last few years. In many situations, communication networks are implemented with electrical interconnections. As desired levels of bandwidth and transmission speed for communication networks increase, it will become more difficult for electrical interconnections to satisfy these levels.
Optical fiber offers a solution to the difficulties affecting conventional electrical interconnections. For example, optical fiber is less susceptible to inductive or capacitive coupling effects than are electrical interconnections. Optical fiber also offers increased bandwidth and substantial avoidance of electromagnetic interference. The advantages of optical fiber become more important as the transmission rates increase.
Many communications networks feature hybrid, optical-electrical semiconductor circuits that employ photodetectors, electrical switches, optical modulators and/or lasers. To handle greater data traffic, an alternative approach uses a photonic switch system, which performs switching operations of light pulses or photons (referred to generally as xe2x80x9clight signalsxe2x80x9d) without the need for converting and re-converting signals between the optical domain to the electrical domain.
However, conventional photonic switches are still subject to a wide variety of disadvantages. Traditional photonic switch systems may not offer any protective features against equipment failures, specifically failures within the photonic switch itself. Moreover, traditional photonic switches do not provide in service, near hitless, bridge and roll capabilities. Bridge and roll capabilities would be useful for switching from a primary photonic switch to a secondary photonic switch to facilitate maintenance, repair and upgrades on the primary photonic switch.
In accordance with the present invention there is provided a photonic switch system comprising a first photonic switch having a plurality of inputs and outputs, a second photonic switch having a plurality of inputs and outputs, a plurality of head-end modules each having an input port for receiving incoming light signals, a first output port and a second output port, the first output port being connectable to a respective input of the first photonic switch and the second output port being connectable to a respective input of the second photonic switch, a plurality of tail-end modules each having an output port for transmitting outgoing light signals, a first input port and a second input port, the first input port being connectable to a respective output of the first photonic switch and the second output port being connectable to a respective output of the second photonic switch.
There is further provided a method of performing a bridge and roll operation on incoming optical signals in a photonic switch system having a first photonic switch connected such that an optical path is established only though the first photonic switch, and having a plurality of head-end and tail-end modules and a second photonic switch the method comprising the steps of: connecting a second output port of each module of the plurality of head-end modules to a respective input of the second photonic switch and connecting a second input port of each of the plurality of the tail-end modules to a respective output of the second photonic switch; re-configuring the head-end modules and the tail-end modules so that the incoming light signals that are received on the input ports of the head-end modules are re-routed through the second photonic switch to the output ports of the tail-end modules; and disconnecting a first output port of each head-end module from the first photonic switch and disconnecting a first input port of each tail-end module from the first photonic switch.
The bridge and roll method facilitates protection, maintenance, repair and upgrade of the primary photonic switch.
Advantageously, the bridge and roll method may be reversed in order to restore the original inputs and outputs on the primary photonic switch after protection, maintenance, repair or upgrade has been performed.
The present invention also provides a method for consolidating multiple wavelengths or multiple bands of wavelengths into single fibers.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of the specific embodiments of the invention in conjunction with the accompanying figures.